Closure for specimen collection containers

ABSTRACT

A closure for sealing closing a medical specimen container having a container wall defining a container interior and an open end. The closure includes a molded plastic closure frame having a cap portion for positioning over the open end of the container and an insertion portion depending from the cap portion for positioning adjacent the container wall. An elastomeric sheath is formed about the insertion portion of the frame. The elastomeric sheath is to be disposed in resilient frictional engagement with the container wall.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to closures used in combination with specimen collection containers. More particularly, the present invention is directed to an improved closure for blood collection tubes which provides for sealed engagement with the open end of the blood collection tube and which is cost effective to manufacture.

[0003] 2. Description of Related Art

[0004] Medical specimens, such as blood samples and the like, are routinely collected and analyzed in clinical situations for various purposes. Biological materials such as blood are normally collected in a specimen collection container in the shape of an open ended tube. The tube is generally an elongate cylindrical member having one end which is open to permit access into the interior of the tube. The tube is typically provided with a removable closure in the form of a removable plastic cap or a rubber stopper which allows the contents of the tube to be transported without risk of spillage.

[0005] The art has seen various designs for closures and stoppers used in combination with blood collection tubes. One type of closure includes a relatively rigid plastic member which is inserted into the open end of the tube and which provides a seal between the closure and the inner wall of the tube about the open upper end. Closures of this type are manually inserted and removed in order to fill the tube or to remove the contents therefrom. Closures of this type are typically formed by conventional injection or compression molding processes. Such manufacturing processes result in a high quality precision part. Also, molding of plastic parts is generally an efficient method of manufacture which greatly reduces the cost of the closures.

[0006] Another type of closure which is more typically used with evacuated blood tubes is a rubber stopper. Rubber stoppers are inserted into the open end of the tube and may be formed of natural or synthetic rubber or combination thereof. These stoppers provide a resilient elastomeric seal with the inner wall of the tube. Stoppers of this type are preferred as they are easy to handle and provide a reliable seal. Materials forming such rubber stoppers may also include self-closing characteristics. This provides the closure with the ability to permit a small hole or puncture, placed in the stopper,by a hypodermic needle or trocar, to close upon itself once the needle is removed. Such self-closing characteristics allow the interior of the tube to be evacuated so that blood samples may be obtained in an evacuated fashion, as is well known in the art.

[0007] While use of rubber stoppers is preferable to rigid plastic enclosures, as the rubber stoppers provide self-sealing characteristics, are easier to insert and remove, and provide a superior seal, rubber stoppers due to their material construction are more difficult and less cost effective to manufacture. Efficient manufacturing techniques, such as injection and compression molding, may not be employed in forming such rubber stoppers. Other more complicated manufacturing techniques such as compression molding must be employed, greatly increasing the cost of the stopper. As compared with injection molding, compression molding is more time-consuming and costly. Furthermore, it is more difficult to mold complex parts with fine details by compression molding.

[0008] Accordingly, it is desirable to provide an improved tube closure which has the benefits of rubber stoppers in that the stopper is easily inserted and removed and includes self-sealing characteristics so that it may be employed with an evacuated tube, yet be manufactured efficiently and have the precision of molded plastic closures.

SUMMARY OF THE INVENTION

[0009] It is an object of the present invention to provide a closure for a specimen collection container which can be efficiently manufactured.

[0010] It is a further object of the present invention to provide a closure for a blood collection tube which sealingly engages the open end of the tube and provides self-sealing characteristics after being punctured by a trocar.

[0011] It is yet a further object of the present invention to provide a closure for a blood collection tube having the benefits of a self-sealing rubber stopper, and the precision manufacturability of a plastic closure.

[0012] In the efficient attainment of these and other objects, the present invention provides a closure for sealing the open end of a medical specimen container. The container includes a container wall defining an interior and an open end. The closure includes a molded plastic closure frame including a cap portion for positioning over the open end of the container. The closure frame includes an insertion portion depending from the cap for positioning adjacent the container wall. An elastomeric sheath is formed about the insertion portion of the frame. The elastomeric sheath is disposed in resilient frictional engagement with the container wall.

[0013] Preferably the insertion portion of the closure frame includes a plurality of a deflectable splines for resilient positioning interiorly about the container wall. The cap portion of the frame may be formed into an annular configuration having a central aperture therethrough. The splines extend circumferentially about the central aperture. The elastomeric sheath is designed to fill the central aperture of the cap portion and may be formed of a self-sealing material.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a top perspective view of the cap assembly of the present invention positioned over the open end of a specimen tube which receives the cap assembly.

[0015]FIG. 2 is a top perspective view of the cap assembly of the present invention.

[0016]FIG. 3 is a bottom perspective view of the cap assembly of FIG. 3.

[0017]FIG. 4 is a vertical cross-sectional view of the cap assembly of FIG. 3 inserted into the open end of a specimen collection tube.

[0018]FIG. 5 is a top perspective view of the frame of the cap assembly of the present invention.

[0019]FIG. 6 is a bottom perspective view of the frame of FIG. 5.

[0020]FIG. 7 is a vertical cross-sectional view of the frame of FIG. 5 taken along the line 7-7 thereof.

[0021]FIG. 8 is a horizontal cross-sectional view of the frame of FIG. 7 taken through the line 8-8 thereof.

[0022]FIG. 9 is a vertical cross-sectional view of the cap assembly of FIG. 2.

[0023]FIG. 10 is a horizontal cross-sectional view of the cap assembly of FIG. 9 taken through the line 10-10 thereof.

[0024]FIG. 11 is a vertical cross-section of a further embodiment of the cap assembly of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The present invention may be described as a closure for a specimen collection container. More particularly, the present invention, in a preferred embodiment, takes the form of a closure cap assembly for a specimen collection tube.

[0026] Referring to FIGS. 1-3, the present invention provides a closure cap assembly 10 for sealingly closing the open end 12 of a specimen collection tube 14. Collection tube 14 is of a type well known in the art and typically includes a cylindrical container wall 16 terminating at rim 18 at open end 12 and being closed at the opposed end by end wall 20. Container wall 16 and end wall 20 define a container interior 22.

[0027] Cap assembly 10 includes a frame portion 24 and an elastomeric sheath 26. Frame portion 24 is shown by phantom lines in FIG. 3. Elastomeric sheath 26 conforms about frame portion 24 so as to provide resilient sealed frictional engagement with the container wall 16 of specimen collection tube 14 so as to close container interior 22, as shown in FIG. 4. Frame portion 24 is preferably molded of a substantially rigid plastic material. Frame portion 24 thereby provides structural rigidity to cap assembly 10. Elastomeric sheath 26 is preferably formed of an elastomeric material that is molded or otherwise formed over frame portion 24. Elastomeric sheath 26 thereby provides the resilient sealed engagement between frame portion 24 and container wall 26. Cap assembly 10 therefore provides a closure for a medical specimen container having the structural rigidity of a molded plastic cap and the resilient sealing ability of an elastomeric cap.

[0028] Referring now to FIGS. 5-8, frame 24 includes a cap portion 28 and an insertion portion 30 depending therefrom. Cap portion 28 includes an annular member 32 which defines a central aperture 34 therethrough. Annular member 32 is substantially planar in shape and includes a bottom face 36 opposite from a top face 38. When cap assembly 10 is inserted into open end 12 of collection tube 14, rim 18 of tube 14 is preferably in abutting engagement with bottom face 36 of annular member 32.

[0029] Annular member 32 of frame 24 is perimetrically bounded by an upstanding cylindrical wall 52. Cylindrical wall 52 defines a cap interior 54 which is preferably in coaxial communication with central aperture 34. Outer surface 56 of cylindrical wall 52 is provided with a plurality of gripping ribs 58 circumferentially spaced therealong. Gripping ribs 58 enhance the ability of cap assembly 10 to be finger-grasped and manipulated into and out of engagement with tube 14.

[0030] Insertion portion 30 of frame 24 includes a plurality of elongate radially spaced splines 40 depending from annular member 32. Splines 40 define a central passageway 42 in co-axial communication with central aperture 34. Splines 40 are preferably placed to further divide bottom face 36 into an inner annular flange surface 43 and an outer annular flange surface 45. Each spline 40 is cantileverally deflectable about bottom face 36 and includes a proximal spline portion 46 adjacent bottom face 36 and a distal spline portion 48 at the free end thereof.

[0031] Additionally, each proximal spline portion 46 is contiguous with each distal spline portion 48 along juncture line 50. Preferably, each proximal spline portion 46 is formed at an obtuse angle to each distal spline portion 48 so that the plurality of juncture lines 50 define the maximum diameter of insertion portion 30. Preferably, each proximal spline portion 46 tapers outward towards juncture line 50 and each distal spline portion 48 preferably tapers inward from juncture line 50 towards central passageway 42. Such construction assists in inserting cap assembly 10 into open end 12 of tube 14. While cap assembly 10 is shown to have an insertion portion which provides sealing resilient engagement with the interior surface of tube 14, it is also contemplated by the present invention that cap assembly 10 may be formed so that insertion portion 30 engages the exterior surface of tube 14.

[0032] Referring now to FIGS. 9 and 10, the preferred configuration of elastomeric sheath 26 on frame 24 will be described in further detail. Sheath 26 is formed over frame 24 so as to include a first portion 60 which encases the plurality of splines 40, and an integral second portion 62 which spans central aperture 34 and passageway 42 immediately adjacent inner bottom flange surface 43. As sheath 26 conforms to the shape of frame 24, cap assembly 10 will therefore include a beveled surface 64 where sheath 26 encases distal spline portion 48 of the plurality of splines 40. Sheath 26 preferably terminates at a sheath edge 66 in abutting engagement with outer bottom flange surface 45.

[0033] When cap assembly 10 is inserted into open end 18 of a specimen collection tube, as shown in FIGS. 1 and 4, beveled surface 64 initially presents a tapered lead-in to container wall 16. As insertion portion 30 of cap assembly 10 is further inserted into container interior 22, splines 40 are caused to deflect inwardly towards passageway 42 with the maximum deflection occurring as juncture line 50 is inserted past rim 18. The deflection of splines 40 results in a radial contacting force F being asserted against container wall 16 which provides a frictional or interference fit between cap assembly 10 and container wall 16. Contacting force F also maximizes the resilient sealing engagement of elastomeric sheath 26 against container wall 16 so as to better seal the container.

[0034] In order to access the interior 22 of tube 14, cap assembly 10 may be removed manually. Additionally, interior 22 may be accessed for blood collection or removal purposes by puncturing second sheath portion 62 with a sharpened trocar (not shown). The elastomeric properties of second sheath portion 62 allow it to self-seal after such a trocar is withdrawn and to maintain the sealing integrity of cap assembly 10 with the specimen collection tube. Cap assembly 10 therefore provides sealed closure of tube 14 so that tube 14 may be employed as an evacuated tube which facilitates the drawing of blood using a trocar through second sheath portion 62. Cap assembly 10 also provides a closure for a specimen collection tube which exhibits the self-sealing characteristics and the resilient container-wall-engagement of a fully-elastomeric closure device and the precise manufacturability and structural strength of a rigid plastic closure device.

[0035] A further embodiment of the cap assembly of the present invention is shown in FIG. 11. Cap assembly 10 a includes a frame portion 24 a having splines 40 a and an elastomeric sheath 26 a. Sheath 26 a is substantially similar to sheath 26 of FIG. 4. Frame portion 26 a includes a depending annular skirt 27 a extending along the exterior of tube wall 16 a. The distal end of skirt 27 a includes an inwardly directed rim 29 a for engagement about tubular wall 16 a. Skirt 27 a forms a vapor seal with tubular wall 16 a.

[0036] As the cap assembly 10 a is removed, there exists the possibility that as air enters the evacuable tube, vapors in the tube may escape. These vapors may contain minute amounts of body fluids. The addition of skirt 27 a and the vapor seal adjacent tubular wall 1 6a minimizes the chance of said vapors being airborne.

[0037] Various other changes and modifications can be made to the invention, and it is intended to include all such changes and modifications as come within the scope of the invention as is set forth in the following claims. 

What is claimed is:
 1. A closure for sealing closing a medical specimen container having a container wall defining a container interior and an open end, said closure comprising: a closure frame including a cap portion for positioning over the open end of said container and an insertion portion depending from said cap portion for positioning adjacent said container wall; and an elastomeric sheath formed about said insertion portion of said frame, said elastomeric sheath being positioned in resilient frictional engagement with said container wall.
 2. A closure of claim 1 wherein said insertion portion is formed for positioning within said container interior.
 3. A closure of claim 1 wherein said insertion portion includes a plurality of deflectable splines for resilient positioning adjacent said container wall.
 4. A closure of claim 2 wherein said sheath is formed about said splines of said insertion portion.
 5. A closure of claim 4 wherein said splines including said sheath thereabout provide for resilient engagement with said container wall.
 6. A closure of claim 5 wherein said splines including said sheath thereabout are insertable within said container interior.
 7. A closure of claim 3 wherein said frame includes an annular body forming said cap portion, said annular body having a central aperture and wherein said splines extend circumferentially about said central aperture.
 8. A closure of claim 7 wherein said elastomeric sheath fills said central aperture of said annular body.
 9. A closure of claim 3 wherein said frame is formed of molded plastic.
 10. A closure of claim 9 wherein said sheath is formed of an elastomeric polymer.
 11. A closure of claim 10, wherein said elastomeric polymer is molded over said frame.
 12. A closure of claim 8 wherein said cap annular body includes a first annular surface for positioning over said opening of said tube. 